Method and apparatus capable of accurately estimating/determining power percentage of battery based on confidence levels determined from resultant information of multiple different fuel gauge operations and/or information of battery history, aging factor, sleep time, or battery temperature

1. A method for estimating a battery power percentage of a battery, comprising: performing a first fuel gauge operation upon the battery; and using the first fuel gauge operation to generate the battery power percentage of the battery by referring to information measured by a second fuel gauge operation performed upon the battery, the second fuel gauge operation being different from the first fuel gauge operation; wherein the first fuel gauge operation is performed based on the information measured by the second fuel gauge operation performed upon the battery so as to generate the battery power percentage of the battery; and, the information, measured by the second fuel gauge operation, comprises a power/energy amount charged for or discharged from the battery or a battery current passing through the battery.

2. The method of claim 1 , wherein the first fuel gauge operation is a voltage-based fuel gauge operation, and the second fuel gauge operation is a Coulomb-counter-based fuel gauge operation.

3. The method of claim 1 , wherein the using step comprises: using the second fuel gauge operation to measure a power/energy amount charged for or discharged from the battery during a time interval; calculating a battery cell voltage of the battery by referring to the measured power/energy amount; and generating the battery power percentage of the battery by referring to a mapping table of the first fuel gauge operation according to the calculated battery cell voltage of the battery, the mapping table defining a relationship between the calculated battery cell voltage of the battery and the battery power percentage of the battery.

4. The method of claim 3 , wherein the calculating step comprises: deriving a battery current passing through the battery according to the measured power/energy amount and the time interval; and calculating the battery cell voltage of the battery according to the derived battery current, a resistance of the battery, and an external battery voltage measured by the first fuel gauge operation.

5. The method of claim 1 , wherein the using step comprises: using the second fuel gauge operation to measure a battery current passing through the battery; calculating a battery cell voltage of the battery by referring to the measured battery current; and generating the battery power percentage of the battery by referring to a mapping table of the first fuel gauge operation according to the calculated battery cell voltage of the battery, the mapping table defining a relationship between the calculated battery cell voltage of the battery and the battery power percentage of the battery.

6. The method of claim 5 , wherein the calculating step comprises: calculating the battery cell voltage of the battery according to the measured battery current, a resistance of the battery, and an external battery voltage measured by the first fuel gauge operation.

7. The method of claim 1 , further comprising: performing the first fuel gauge operation to estimate a first value of power/energy amount charged for or discharged from the battery; performing the second first fuel gauge operation to measure a second value of power/energy amount charged for or discharged from the battery; and comparing the first value with the second value determine whether to trigger the using step.

8. The method of claim 7 , wherein the comparing step comprises: calculating a difference ratio between the first value and the second value; and determining to perform the using step when the difference ratio is higher than a specific threshold.

9. The method of claim 1 , further comprising: using the battery power percentage generated by the first fuel gauge operation to calibrate or adjust another battery power percentage measured by the second fuel gauge operation.

10. A power management apparatus for estimating a battery power percentage of a battery, comprising: a memory device; a controller, coupled to the memory device, configured for loading program code(s) from the memory device to: perform a first fuel gauge operation upon the battery; and use the first fuel gauge operation to generate the battery power percentage of the battery by referring to information measured by a second fuel gauge operation performed upon the battery, the second fuel gauge operation being different from the first fuel gauge operation; wherein the first fuel gauge operation is performed based on the information measured by the second fuel gauge operation performed upon the battery so as to generate the battery power percentage of the battery; and, the information, measured by the second fuel gauge operation, comprises a power/energy amount charged for or discharged from the battery or a battery current passing through the battery.

11. The power management apparatus of claim 10 , wherein the first fuel gauge operation is a voltage-based fuel gauge operation, and the second fuel gauge operation is a Coulomb-counter-based fuel gauge operation.

12. The power management apparatus of claim 10 , wherein the controller is arranged for: using the second fuel gauge operation to measure a power/energy amount charged for or discharged from the battery during a time interval; calculating a battery cell voltage of the battery by referring to the measured power/energy amount; and generating the battery power percentage of the battery by referring to a mapping table of the first fuel gauge operation according to the calculated battery cell voltage of the battery, the mapping table defining a relationship between the calculated battery cell voltage of the battery and the battery power percentage of the battery.

13. The power management apparatus of claim 12 , wherein the controller is arranged for: deriving a battery current passing through the battery according to the measured power/energy amount and the time interval; and calculating the battery cell voltage of the battery according to the derived battery current, a resistance of the battery, and an external battery voltage measured by the first fuel gauge operation.

14. The power management apparatus of claim 10 , wherein the controller is arranged for: using the second fuel gauge operation to measure a battery current passing through the battery; calculating a battery cell voltage of the battery by referring to the measured battery current; and generating the battery power percentage of the battery by referring to a mapping table of the first fuel gauge operation according to the calculated battery cell voltage of the battery, the mapping table defining a relationship between the calculated battery cell voltage of the battery and the battery power percentage of the battery.

15. The power management apparatus of claim 14 , wherein the controller is arranged for calculating the battery cell voltage of the battery according to the measured battery current, a resistance of the battery, and an external battery voltage measured by the first fuel gauge operation.

16. The power management apparatus of claim 10 , wherein the controller is arranged for: performing the first fuel gauge operation to estimate a first value of power/energy amount charged for or discharged from the battery; performing the second first fuel gauge operation to measure a second value of power/energy amount charged for or discharged from the battery; and comparing the first value with the second value determine whether to trigger using the first fuel gauge operation to generate the battery power percentage of the battery by referring to the information measured by the second fuel gauge operation performed upon the battery.

17. The power management apparatus of claim 16 , wherein the controller is arranged for: calculating a difference ratio between the first value and the second value; and determining to perform the first fuel gauge operation to generate the battery power percentage of the battery by referring to the information measured by the second fuel gauge operation performed upon the battery when the difference ratio is higher than a specific threshold.

18. The power management apparatus of claim 10 , wherein the controller is arranged for using the battery power percentage generated by the first fuel gauge operation to calibrate or adjust another battery power percentage measured by the second fuel gauge operation.